Fairfax County bans high school athletes from drinking high-caffeine beverages such as Red Bull.

Concerned that a growing number of Fairfax County's high school athletes were guzzling highly caffeinated energy drinks to boost their sports performance, school system officials have banned the beverages before, during and after school.

The ban went into effect toward the end of the winter sports season, after a string of Fairfax County student athletes required medical attention for heart trouble induced by the drinks' sugary caffeine punch coupled with strenuous exercise.

"We'd been seeing kids drinking two or three of these things prior to games in the locker room," said Paul Jansen, director of the school system's office of student activities and athletics. "We're saying, don't drink a case of Red Bull and go out there because you have no idea what can happen to you."

The ban does not extend to the general student population at every Fairfax County high school. But if student athletes are caught drinking an energy beverage, they will now face possible sanctions from their coach, including game suspensions or extra conditioning exercises.

"Worst case scenario, it can kill you," Jansen said.

THE MOST POPULAR energy drink, Red Bull, was introduced by an Austrian company in the United States nine years ago as a vodka mixer at bars. Since then, the drink has spawned dozens of imitators, including "AMP," "Pimp Juice," "Monster Khaos Energy,” "Twisted Chopper" and "Who's Your Daddy."

"Energy drinks are one of the fastest-growing segments of the beverage industry," said Gary Hemphill, of the market research firm Beverage Marketing Corp.

The $3 billion energy drink industry is largely targeted at teenagers and young adults, Hemphill said.

One 8.3 ounce can of Red Bull contains 80 milligrams of caffeine, twice as much as a 12 ounce soda or roughly the equivalent of an 8 ounce cup of coffee. Red Bull also contains "energy boosting" additives like sugar, taurine, which supposedly boosts caffeine's effects, and vitamin B12.

Another popular product, Full Throttle, made by the Coca-Cola company, comes in a 16 ounce can and contains even more caffeine. One can of Full Throttle boasts 144 milligrams of caffeine, four times as much as a soda. The drink also contains ginseng extract, guarana (also a stimulant) and various B vitamins.

Jansen said the drinks' ergonomic — or performance enhancing — claims have proven tempting to high school athletes seeking an edge over their competitors. Downing a few energy drinks, they believe, might give them an advantage over other athletes in swimming, track races, basketball games and more, he said.

"Would any parent let their child drink two gallons of coffee? That's just about what was happening," Jansen said.

LITTLE DEFINITIVE research has been conducted into the effects of high-caffeine doses on athletes. But athletic trainers believe that common sense suggests it is a potentially dangerous combination.

"From a parent's perspective, if you don't know for sure if this is harmful, why would you take the chance?" said Ellen Satlof, spokeswoman of the National Athletic Trainers Association in New York City.

Prior to the Fairfax County school system's ban, a handful of student athletes experienced problems from mixing energy drinks with sports, said Jon Almquist, athletic training specialist in the office of student activities and athletics.

"The contents can dangerously stimulate the heart rate," he said. "We're not going to allow them to drink this on our time. We want to prevent kids from having to go to the hospital."

The students were referred to a physician after being diagnosed with tachycardia, an abnormally rapid heart beat of more than 100 beats per minute.

During the 2004-2005 school year, Fairfax County's office of risk management took similar steps to ban weight-loss supplements containing ephedrine during school hours and activities.

According to research conducted by the American Medical Association and the American College of Sports Medicine, supplements containing ephedrine increase the risk of heart irregularities, disturbances of the central nervous system, gastrointestinal problems and stroke.

APART FROM student athletes, it probably comes as little surprise that teenagers are turning to fruity energy drinks. With high school classes in Fairfax County generally starting at 7:20 a.m., bleary-eyed teens have long sought ways to perk up for first period.

Penny McConnell, director of the school system's office of food and nutrition services, said she has noticed even middle school students bringing cups of coffee to class.

"I see students bringing it in," she said. "I was over at Glasgow Middle School the other day and saw a bunch of kids getting out of their parent's cars carrying cups of Starbucks."

The school system does not sell either coffee or energy drinks, McConnell said. It does, however, sell in its vending machines "sports drinks" like Powerade, which does not contain the potentially harmful additives.